Ni-cr-al chromium carbide powder

ABSTRACT

Disclosed herein are improved chromium carbide alloy which possess improved properties as related to previous developments. The utilization of aluminum in the alloy can enhance the high temperature oxidation resistance. Embodiments of alloys were designed to simultaneously possess 1) a low liquidus temperature which enables easy atomization on an industrial scale, and 2) a microstructure of a gamma matrix and Cr7C3 carbide precipitates which enables high temperature stability and retention of advantageous properties at high temperatures.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application claims from the benefit of U.S. application Ser. No. 62/868135, filed Jun. 28, 2019, and entitled “NI—CR—AL CHROMIUM CARBIDE POWDER”, and U.S. application Ser. No. 62/969,474, filed Feb. 3, 2020, and entitled “NI—CR—AL CHROMIUM CARBIDE POWDER”, the entirety of each of which is incorporated by reference herein.

BACKGROUND Field

The embodiments of this disclosure generally relate to nickel-based alloys containing chromium carbides which serve as effective feedstock.

Description of the Related Art

Many commercially available nickel-based chromium carbide powders for thermal spray applications are produced via agglomerating and sintering or mechanical cladding processes. These manufacturing processes involve mechanical blending of individual constituents. For example, chromium carbide powder can be blended with a nickel-chromium alloy powder, sintered together and spheroidized to form a new powder of individual particles consisting of a blend of chromium carbide and nickel-chromium constituents. Manufacturing methods like this are costly and time consuming. In addition, the resultant powders produced from these processes are prone to decarburization and oxidation during the thermal spray process which can alter the chemistry of the applied coating in negative ways. These types of powders have also been shown to produce low deposit efficiencies during the spray process. Meaning during the thermal spray application, only 25-35% of the powder ends up forming the coating and the remaining powder is lost.

In contrast, the atomization process takes a molten alloy as the feed stock and injects the molten metal through a nozzle. High pressure gas or water is used to impinge on the molten stream of metal passing through the nozzle which turns the stream into individual droplets. These droplets then solidify into homogenous particles of a singular alloy. For example, chromium, nickel and carbon can be melted together forming a singular alloy constituent. During the atomization process, the chromium carbides precipitate out of the molten metal forming individual chromium carbide particles in the nickel matrix. The advantages of this manufacturing process are lower costs and faster processing times. Atomized powders do not decarburize or oxidize as readily during the spray process and higher deposit efficiencies are achievable.

Currently there exist several atomized nickel-based alloys which form chromium carbide precipitates during the atomization process. These alloys are commonly used to form wear resistant coatings on critical components in oil and gas, automotive, aerospace, and other industrial applications. The following US patents present atomized nickel-based alloys which form chromium carbide precipitates: U.S. Pat. Nos. 5,863,618, 6,071,324 and 6,254,704, the entirety of each of which is hereby incorporated by reference in its entirety. All these examples of prior art explicitly describe an alloy containing only chromium, nickel and carbon with the matrix phase being a Ni-Cr alloy.

A fourth patent, U.S. Pat. No. 8,906,130 which is hereby incorporated by reference in its entirety, describes an alloy containing molybdenum in addition to chromium, nickel and carbon. Thus, the alloy forms bimetallic chromium and molybdenum carbides within a Ni-Cr-Mo alloy matrix.

A technical paper published in the Journal of Thermal Spray Technology on Dec. 9, 2016 describes an alloy system similar the teachings of this disclose. Zhu, Hong-Bin, et al. “Microstructure and Sliding Wear Performance of Cr7C3-(Ni,Cr)3(Al,Cr) Coating Deposited from Cr7C3 In Situ Formed Atomized Powder.” Journal of Thermal Spray Technology, vol. 26, no. 1-2, 2016, pp. 254-264., doi:10.1007/s11666-016-0498-1, hereby incorporated by reference in its entirety.

However, the alloy system described in this paper teaches the addition of boron as critical for reducing intergranular fracture or brittleness of the alloy's matrix phase. The alloy system of this disclosure is specifically designed to be boron free. Furthermore, the paper teaches a Cr to C ratio in the alloy of 7:3. However, since some of the Cr ends up in the matrix of the alloy and not in the formation of carbide, it is necessary to add extra Cr to maintain this ratio. The paper teaches the Cr addition would be between 4-7 wt. % extra. Embodiments of this disclosure were produced using an additional Cr content of 9 wt. % after achieving the initial 7:3 Cr to C ratio. Finally, the paper claims the matrix phase of the alloy is an intermetallic gamma prime phase with the composition of (Ni,Cr)₃(Al,Cr).

SUMMARY

Disclosed herein are embodiments of a thermal spray feedstock comprising Ni, Al: about 1.0 wt. %-about 3.0 wt. %, C: about 3.5 wt. %-about 5.5 wt. %, Cr: about 47.5 wt. %-about 57.5 wt. %, and CrC carbides. In some embodiments, the feedstock can comprise Al: about 1.5 wt. %-about 2.5 wt. %, C: about 4.0 wt. %-about 5.0 wt. %, and Cr: about 50.0 wt. %-about 55.0 wt. %.

In some embodiments, the feedstock can comprise Al: about 1.5 wt. % to 7 wt. %, C: 3-5.75 wt. %, Cr: 41-60 wt. %, Ni: balance. In some embodiments, B can be used in place of C. In some embodiments, the alloy can further comprise Cobalt up to 10 wt. %. In some embodiments, the alloy can further comprise V up to 10 wt. %. In some embodiments, the alloy can further comprise W up to 1 wt. %.

In some embodiments, the CrC carbides are Cr₇C₃ carbides. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a total Cr₇C₃ fraction at 1300K of about 40 mole % or greater. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a total Cr₇C₃ fraction at 1300K of about 50 mole % or greater. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a total Cr₇C₃ fraction at 1300K of about 60 mole % or greater. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a temperature range of about 400K when Cr₇C₃ carbides are the only carbides present. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a temperature range of 750K of when Cr₇C₃ are the only carbides present. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a temperature range of 1000K when Cr₇C₃ are the only carbides present.

In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a temperature range of a single-phase FCC_A1 matrix of about 200K. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a temperature range of a single-phase FCC_A1 matrix of about 400K. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a temperature range of a single-phase FCC_A1 matrix of about 600K.

The thermal spray feedstock of any one of claims 1-12, wherein the feedstock is characterized by having, under thermodynamic conditions, a weight percentage of aluminum content in a single phase FCC_A1 matrix at 1500K of above about 2%.

In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a weight percentage of aluminum content in a single phase FCC_A1 matrix at 1500K of above about 4%. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a weight percentage of aluminum content in a single phase FCC_A1 matrix at 1500K of above about 6%. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a liquidus temperature of below about 1975K. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a liquidus temperature of below about 1950K. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, a liquidus temperature of below about 1900K.

In some embodiments, the feedstock can be characterized by having, under thermodynamic conditions, a matrix containing both a gamma phase and a beta phase both possessing an FCC structure, gamma being disordered and beta being ordered per conventional terminology. The beta content can range from 0 volume % up to a 1:1 gamma/beta ratio. In heavy oxidation prone environments gamma/beta ratio is 2.3 or lower, preferably between 1 and 1.5. To clarify, the gamma/ beta ratio defines the matrix volume fraction, the entire alloy microstructure still containing 40-60 mol. % Cr₇C₃ carbides in that matrix. In some embodiments, the alloy can have a single phase matrix. In some embodiments, the alloy can have a dual phase matrix.

In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation 0.7≥y+6.36x, x being equal to a weight % of Al in an FCC_A1 matrix at 1500K and y being equal to a phase mole fraction of Cr₇C₃ at 1500K. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation (−6)≥y−0.20x ≥(−9), x being equal to a wt. % Ni and y being equal to a wt. % Al. In some embodiments, the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation (−0.4)≥y−0.1x≥(−1.5), x being equal to a wt. % Cr and y being equal to a wt. % C.

In some embodiments, the thermal spray feedstock can be boron free.

In some embodiments, the coating has at least about 40 area % of Cr₇C₃ particles. In some embodiments, the coating has at least about 50 area % of Cr₇C₃ particles. In some embodiments, the coating has at least about 60 area % of Cr₇C₃ particles. In some embodiments, the coating has a matrix comprising a total Al content of about 4 weight % or higher. In some embodiments, the coating has a matrix comprising a total Al content of about 6 weight % or higher. In some embodiments, the coating has a matrix comprising a total Al content of about 9 weight % or higher.

In some embodiments, the thermal spray feedstock is a powder.

Also disclosed herein are embodiments of hardfacing or hardbanding coating formed from the thermal spray feedstock as disclosed herein.

In some embodiments, the coating has at least about 40 area % of Cr₇C₃ particles. In some embodiments, the coating has at least about 50 area % of Cr₇C₃ particles. In some embodiments, the coating has at least about 60 area % of Cr₇C₃ particles. In some embodiments, the coating has a matrix comprising a total Al content of about 4 weight % or higher. In some embodiments, the coating has a matrix comprising a total Al content of about 6 weight % or higher. In some embodiments, the coating has a matrix comprising a total Al content of about 9 weight % or higher.

In some embodiments, the coating has an ASTM G65B volume loss of less than about 35 mm³. In some embodiments, the coating has an ASTM G65B volume loss of less than about 25 mm³. In some embodiments, the coating has an ASTM G65B volume loss of less than about 15 mm³. In some embodiments, the coating has an ASTM G32 volume loss of less than about 5 mm³ after 1200 minutes. In some embodiments, the coating has an ASTM G32 volume loss of less than about 4 mm³ after 1200 minutes. In some embodiments, the coating has an ASTM G32 volume loss of less than about 3mm ³ after 1200 minutes.

In some embodiments, the coating has a Vickers hardness of greater than about 500 HV_(0.3). In some embodiments, the coating has a Vickers hardness of greater than about 600 HV_(0.3). In some embodiments, the coating has a Vickers hardness of greater than about 700 HV_(0.3). In some embodiments, the coating can last over about 500 hours before failing under ASTM B117 salt spray testing. In some embodiments, the coating can last over about 750 hours before failing under ASTM B117 salt spray testing. In some embodiments, the coating can last over about 1000 hours before failing under ASTM B117 salt spray testing.

Also disclosed herein are embodiments of a powder feedstock comprising Ni, Al: about 2.0 wt. %-about 7.0 wt. %, C: about 3.5 wt. %-about 5.75 wt. %, and Cr: about 41.0 wt. %-about 60.0 wt. %, and wherein the powder feedstock is configured to form CrC carbides.

Also disclosed herein are embodiments of a powder feedstock comprising Ni, Al: about 5.6 wt. %-about 8.4 wt. %, C: about 3.6 wt. %-about 5.4 wt. %, Cr: about 37.6 wt. %-about 56.4 wt. %, and wherein the powder feedstock is configured to form CrC carbides.

Also disclosed herein are embodiments of a powder feedstock comprising Ni, Al: about 1.6 wt. %-about 2.4 wt. %, C: about 3.6 wt. %-about 5.4 wt. %, Cr: about 42 wt. %-about 63 wt. %, and wherein the powder feedstock is configured to form CrC carbides.

Also disclosed herein are embodiments of powder feedstock comprising Ni. Al: about 1.0 wt. % - about 3.0 wt. %, C: about 1.5 wt. % - about 4.5 wt. %, and Cr: about 45 wt. %-about 60 wt. %, wherein the powder feedstock is configured to form CrC carbides.

Also disclosed are embodiments of a hardfacing or hardbanding coating as disclosed herein.

Further disclosed herein are embodiments of a thermal spray feedstock as disclosed herein.

Further disclosed herein are embodiments of a method of forming a coating from a thermal spray feedstock as disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a thermodynamic solidification profile of a P105-X3 alloy.

FIG. 2 illustrates a thermodynamic solidification profile of a P105-X2 alloy.

FIG. 3 illustrates a scanning electron micrograph of a P105-X3 alloy manufactured as a ˜40 g ingot.

FIG. 4 illustrates a scanning electron micrograph of a P105-X3 alloy (left) manufactured as a ˜40 g ingot as compared to a P105-X3 alloy (right) manufactured as ˜40 g ingot.

FIG. 5 illustrates a thermodynamic solidification profile of a P105-X8 alloy.

FIG. 6 illustrates a scanning electron micrograph of a P105-X8 alloy manufactured as a ˜40 g ingot.

FIG. 7 illustrates a thermodynamic solidification profile of a P105-X16 alloy.

DETAILED DESCRIPTION

Embodiments of the present application include but are not limited to hardfacing/hardbanding materials, alloys or powder compositions used to make such hardfacing/hardbanding materials, methods of forming the hardfacing/hardbanding materials, and the components or substrates incorporating or protected by these hardfacing/hardbanding materials.

Embodiments of this disclosure are designed specifically to form a gamma Ni—Cr—Al matrix that is free of all other secondary and intermetallic phases. A gamma (γ) matrix, as opposed to a gamma prime (γ′) matrix is advantageous due to the higher toughness of the γ phase. In some embodiments, it can be advantageous for the matrix to be composed of both gamma (γ) phase and beta (β) phase ranging from 0% β up to a 1:1 ratio between gamma and beta. Beta is the common name for the FCC ordered structure commonly comprising nickel and aluminum as the primary constituents at roughly a 1:1 ratio.

In many applications, components thermally sprayed or hardfaced with a coating are exposed to elevated temperatures such as, for example 400° C. to 900° C. In many applications the most common type of hardfacing material used is tungsten carbide (WC/W₂C). Tungsten carbide has proven to be an effective hardfacing material for resisting a variety of wear mechanisms and increasing the life of the components it is applied onto. However, there are two disadvantages of tungsten carbide based hardfacing. This first of these is cost. Tungsten carbide represent the premium end of the hardfacing product portfolio and from a materials cost perspective is generally the most expensive commercially viable hardfacing material. The second disadvantage of tungsten carbide materials is their properties begin to degrade at elevated temperatures, above 450° C. This makes tungsten carbide less suited for high temperature applications. The embodiments of the present disclosure, unlike tungsten carbide materials, provide a hardfacing that is more cost effective and stable to higher temperatures.

Further, this disclosure discusses chemistries uniquely suited to a gas atomization process. Through control of the solidification of the alloy, the manufacturing ease of the disclosed alloy system is increased. Secondly, the disclosed alloys are designed to form an aluminum containing gamma matrix, whereas previous CrC materials only utilize Ni, Cr, and/or Mo. The aluminum containing matrix provides enhanced properties in the disclosed alloy systems most notably improved high temperature oxidation behavior. Aluminum cannot simply be doped into the Ni—Cr—C system to produce the desired effects however, as detrimental aluminides will form in most cases. Furthermore, as described, the matrix and carbide phase stability, and liquidus temperature were also specifically designed for improved performance and manufacturability.

The disclosure accomplishes an improved chromium carbide (CrC) type material which are used in a variety of applications. Conventional CrC type materials are made through the agglomerating and sintering processes. Such processes are relatively expensive and produce low deposit efficiencies when thermally sprayed. CrC have been manufactured using the gas atomization processes previously whereby an “agglomerated and sintered chemistry” is directly translated to the gas atomization process. However, the disclosed technology incorporates Al to provide high temperature oxidation resistance. The manufactured powders can be used in the HVOF thermal spray process to provide wear and corrosion resistant coatings.

Thus, embodiments of this disclosure describe a nickel-based atomized alloy containing aluminum, chromium and carbon. Embodiments of the disclosure can form CrC type carbides, such as Cr₇C₃ or Cr₂₃C₆ carbides, within a Ni—Cr—Al matrix. In some embodiments, the alloy compositions of this disclosure are designed to form a matrix containing the maximum amount of Al while maintaining a single-phase gamma face centered cubic (FCC) structured matrix. The matrix and carbides can be found in the powder, and can be retained during application as a hardbanding/hardfacing layer, such as through thermal spraying. The Al in the matrix phase can offer performance benefits such as high temperature stability and oxidation resistance over conventional Ni—Cr or Co—Cr matrices.

The present disclosure describes embodiments of Ni-based atomized powders which during the atomization process can form CrC carbides, such as Cr₇C₃ or Cr₂₃C₆ carbides, in situ. Thus, the powder itself can contain such carbides. The phase fraction of chromium carbide that forms can be on the order of 40-60 vol %. Ins certain applications, the Cr₇C₃ carbide is the carbide phase as it is stable to higher temperatures compared to tungsten carbide, up to 850° C. Chromium carbide is also lower in cost, making the overall alloy less expensive.

Most of the common types of carbide containing thermal spray powders use a Ni—Cr or Co—Cr based matrix as a binder. The matrix acts to bind the carbides together within the powder and coating and provide some degree of toughness. Embodiments of the present disclosure can form, for example, a Ni—Cr—Al single phase γ matrix. The matrix is designed to contain the maximum amount of Al possible while maintaining a single-phase γ FCC crystal structure. In other types of thermal spray coatings, Al is added for high temperature oxidation resistance. The most common of these coatings are MCrAlY bond coats used in the high temperature sections of gas turbine engines. In embodiments of the present disclosure, the high Al content matrix provides enhanced high temperature stability and oxidation resistance compared to conventional Ni—Cr and Co—Cr alloy matrices.

Unlike most carbide based thermal spray powders produced via agglomerating and sintering or mechanical cladding, embodiments of the present disclosure are manufactured via a gas atomization process. The three main advantages of atomized powders are 1) lower manufacturing costs, 2) during the thermal spray process there is less oxidation and decarburization of the powder, and 3) atomized powders generally allow for higher deposit efficiencies.

In one aspect of this disclosure, the alloys can form only Cr₇C₃ carbides between 40-60 (or about 40-about 60) mol. % in a Ni—Cr—Al matrix. The matrix is designed to contain the maximum amount of Al while maintaining a single-phase γ FCC structure.

In one aspect of this disclosure, the alloys can form only Cr₂₃C₆ carbides between 30-60 (or about 30-about 60) mol. % in a Ni—Cr—Al matrix. Such embodiments, are useful for increasing the chromium content of the matrix which is preferably for certain applications such as resistance to metal dusting.

In some embodiments, the feedstock can be characterized by having, under thermodynamic conditions, a matrix containing both a gamma phase and a beta phase both possessing an FCC structure, gamma being disordered and beta being ordered per conventional terminology. The beta content can range from 0 volume % up to a 1:1 gamma/beta ratio. In heavy oxidation prone environments gamma/beta ratio can be 2.3 (or about 2.3) or lower. In some embodiments, the ratio can be between 1 and 1.5 (or about 1 and about 1.5). The gamma/ beta ratio can define the matrix volume fraction, the entire alloy microstructure still containing 40-60 mol. % Cr₇C₃ carbides in that matrix.

As disclosed herein, the term alloy can refer to the chemical composition forming the powder disclosed within, the powder itself, the feedstock itself, a wire, the wire including a powder, the composition of the metal component formed by the heating and/or deposition of the powder, or other methodology, and the metal component.

In some embodiments, alloys manufactured into a solid or cored wire (a sheath containing a powder) for welding or for use as a feedstock for another process may be described by specific chemistries herein. For example, the wires can be used for a thermal spray. Further, the compositions disclosed below can be from a single wire or a combination of multiple wires (such as 2, 3, 4, or 5 wires).

The disclosed alloys can be applied via thermal spray or other hardfacing/hardbanding processes and the particular process is not limiting. For example, plasma transferred arc (PTA), high velocity oxygen fuel (HVOF), high velocity air fuel (HVAF), plasma spray, extreme high-speed laser cladding (EHLA), and conventional laser cladding hardfacing processes can all be used. Further, embodiments of the disclosed alloys can be welded.

Metal Alloy Composition

In some embodiments, the alloy can be fully described by a compositional range. For example, the range can encompass P105-X3 and meet the thermodynamic, microstructural and performance criteria presented in this disclosure.

In some embodiments, any of the alloys described herein can be free of boron (B). In some embodiments, including any or all of the compositions discussed below, the alloys can have, in wt. %, less than 3%, less than 2%, less than 1%, or less than 0.5% boron (or less than about 3%, less than about 2%, less than about 1%, or less than about 0.5% boron). The lack of B in the alloy can be advantageous for atomization and industrial manufacturing purposes as B can be a problematic impurity thereby contaminating other alloy systems.

In some embodiments, the composition can comprise Ni(for example, BAL) and, in weight percent the following elemental ranges:

-   -   Al: 1.0-3.0 (or about 1.0-about 3.0)     -   C: 3.5-5.5 (or about 3.5-about 5.5)     -   Cr: 47.5-57.5 (or about 47.5-about 57.5)

In some embodiments, the composition can comprise Ni(for example, BAL) and in weight percent the following elemental ranges:

-   -   Al: 1.5-2.5 (or about 1.5-about 2.5)     -   C: 4.0-5.0 (or about 4.0-about 5.0)     -   Cr: 50.0-55.0 (or about 50.0-about 55.0)

In some embodiments, the composition can comprise Ni(for example, BAL) and in weight percent the following elemental ranges:

-   -   Al: 1.5-7.0 (or about 1.5-about 7.0)     -   C: 3.0-5.75 (or about 3.0-about 5.75)     -   Cr: 41.0-60.0 (or about 41.0-about 60.0)

In some embodiments, the composition can comprise Ni (for example, BAL) and in weight percent the following elemental ranges:

-   -   Al: 5.6-8.4 (or about 5.6-about 8.4)     -   C: 3.6-5.4 (or about 3.6-about 5.4)     -   Cr: 37.6-56.4 (or about 37.6-about 56.4)

In some embodiments, the composition can comprise Ni (for example, BAL) and in weight percent the following elemental ranges:

-   -   Al: 1.0-3.0 (or about 1.0-about 3.0)     -   C: 1.5-4.5 (or about 1.5-about 4.5)     -   Cr: 45.0-60.0 (or about 45.0-about 60.0)

In some embodiments, any of the above compositions can further comprise one or more of the following Co up to 10 (or about 10) wt. %, V up to 10 (or about 10) wt. %, or W up to 2 (or about 2) wt. %. In some embodiments, B can be used in place of C.

Tables IA-B lists the experimental alloys, in weight percent with the balance Ni, produced in the form of small-scale ingots to conduct this study.

TABLE IA List of Nominal Experimental Alloy Compositions Alloy Al C Cr P105-X1 5.0 5.5 57.0 P105-X2 4.0 5.5 54.0 P105-X3 2.0 4.5 52.5

TABLE IIB List of Nominal Experimental Alloy Compositions Alloy Al B C Co Cr V W P105-X4 2 3 55 10 1 P105-X5 2 3.5 41 4 P105-X6 4 4.5 50 P105-X7 3.25 5.75 59.5 P105-X8 7 4.5 47 P105-X9 2 4.5 55 P105-X10 2 4.5 2 55 P105-X11 2 4 51.5 P105-X12 2 4.5 10 55

The disclosed alloys can incorporate the above elemental constituents to a total of 100 wt. %. In some embodiments, the alloy may include, may be limited to, or may consist essentially of the above named elements. In some embodiments, the alloy may include 2 wt. % (or about 2 wt. %) or less, 1 wt. % (or about 1 wt. %) or less, 0.5 wt. % (or about 0.5 wt. %) or less, 0.1 wt. % (or about 0.1 wt. %) or less or 0.01 wt. % (or about 0.01 wt. %) or less of impurities, or any range between any of these values. Impurities may be understood as elements or compositions that may be included in the alloys due to inclusion in the feedstock components, through introduction in the manufacturing process.

Further, the Ni content identified in all of the compositions described in the above paragraphs may be the balance of the composition, or alternatively, where Ni is provided as the balance, the balance of the composition may comprise Ni and other elements. In some embodiments, the balance may consist essentially of Ni and may include incidental impurities.

In some embodiments, it can be advantageous to maximize chromium content in the matrix. Table IC below details that effort including P105-X9 through X12 from above and further developments P105-X13 through X16.

TABLE IC List of Nominal Experimental Alloy Compositions Measured Cr in No Al C Co Cr Ni Matrix P105-X9 2.0 4.5 55.0 38.5 27.1 P105-X10 2.0 4.5 2.0 55.0 36.5 26.5 P105-X11 2.0 4.0 51.5 42.5 23.7 P105-X12 2.0 4.5 10.0 55.0 28.5 23.6 P105-X13 2.0 3.5 50.0 44.5 33.9 P105-X14 2.0 3.0 60.0 35.0 44.7 P105-X15 2.0 1.5 50.0 46.5 44.5 P105-X16 2.0 2.0 55.0 41.0 43.8

X13 and X16 represent example embodiments of the disclosure. P105-X13 has an elevated Cr in the matrix content while maintaining the desired Cr7C3 phase as the carbide precipitate. P105-X16 has a further elevated Cr content with Cr₂₃C₆ forming the carbide precipitate. The tables below show manufacturing ranges for X13 and X16 with +/−10% (Table ID) and +/−20% (Table IE) tolerances.

TABLE ID With 10% Range No Al C Cr Ni X13 1.8-2.2 3.15-3.85 45.0-55.0 40.05-48.95 X16 1.8-2.2 1.8-2.2 49.5-60.5 36.9-45.1

TABLE IE With 20% Range No Al C Cr Ni X13 1.6-2.4 2.8-4.2 40.0-60.0 35.6-53.4 X16 1.6-2.4 1.6-2.4 44.0-66.0 32.8-49.2

Thermodynamic Criteria

Embodiments of alloys of the disclosure can be fully described by certain equilibrium thermodynamic criteria. The alloys can meet some, or all the described thermodynamic criteria.

The first thermodynamic criteria relates to the alloys abrasion resistance and high temperature stability. As shown in FIG. 1, this criteria is defined as the total mole fraction of Cr₇C₃ carbide present at 1300K [101]. Controlling the phase fraction of Cr₇C₃ carbide can be advantageous. It allows for the alloy to have the correct type of chromium carbide and amount of chromium carbide to provide a good balance of wear resistance and high temperature stability.

In some embodiments, the total Cr₇C₃ fraction at 1300K can be 40 mole % (or about 40 mole %) or greater. In some embodiments, the total Cr₇C₃ fraction at 1300K can be 50 mole % (or about 50 mole %) or greater. In some embodiments, the total Cr₇C₃ fraction at 1300K can be 60 mole % (or about 60 mole %) or greater.

In some embodiments, the carbide phase can be entirely C₂₃C₆ or a mix of Cr₂₃C₆ and Cr₇C₃ and can be generally referred to as the total Cr—C content. In such embodiments, the total Cr—C content at 1300K can be 40 mole % (or about 40 mole %) or greater. In some embodiments, the total Cr—C content at 1300K can be 50 mole % (or about 50 mole %) or greater. In some embodiments, the total Cr—C content at 1300K can be 60 mole % (or about 60 mole %) or greater.

A second thermodynamic criteria relates to the alloys high temperature stability and is defined as the temperature range, starting at the liquidus, when Cr₇C₃ is the only carbide present [102]. Other types of chromium carbide, such as Cr₃C₂, may not be desirable because they have less thermodynamic stability at high temperatures compared to Cr₇C₃. This criteria helps to produce an alloy that contains only Cr₇C₃ carbide as the hard phase to maximize the high temperature stability of the alloy.

In some embodiments, the temperature range in which the only carbide present is Cr₇C₃ can be 400K (or about 400K). In some embodiments, the temperature range in which only carbide present is Cr₇C₃ can be 750K (or about 750K). In some embodiments, the temperature range in which the only carbide present can be Cr₇C₃ is 1000K (or about 1000K).

A third thermodynamic criteria relates to the alloy's matrix phase. It can be defined as the single-phase FCC_A1 (Al designating the FCC phase as a disordered phase as opposed to an ordered phase) temperature range. The single-phase FCC_A1 temperature range is the temperature range when FCC_A1 is the only phase present, besides M₇C₃ (e.g., Cr₇C₃). As shown in FIG. 2, the temperature range starts at the matrix formation temperature and ends when the first phase other than FCC_A1 forms [201]. This criteria serves as a way to produce a matrix that will be single-phase γ. The benefits of having a single-phase γ matrix is to maximize the toughness of the alloy. It is well known in metallurgy that an FCC crystal structure is relatively tough compared to other crystal structures. In addition, having the matrix single phase ensures other detrimental or embrittling phases will not form, which could reduce the overall toughness of the alloy.

In some embodiments, the single-phase FCC_A1 range can be greater than 200K (or about 200K). In some embodiments, the single-phase FCC_A1 range can be greater than 400K (or about 400K). In some embodiments, the single-phase FCC_A1 range can be greater than 600K (or about 600K).

A fourth thermodynamic criterial relates to the Al content in the single-phase FCC_A1 matrix. This criteria is defined as the weight % of Al in FCC_A1 at 1500K [202]. Tracking the weight % Al content in the FCC_A1 matrix allows for the design of an alloy with a maximum amount of Al in the matrix phase, while maintaining a single-phase FCC_A1 matrix. The primary function of the Al in the γ matrix phase is to enhance the alloy's high temperature stability and oxidation resistance. This criteria is advantageous for designing an alloy with optimized high temperature properties.

In some embodiments, the Al in FCC_A1 at 1500K can be above 2 weight % (or about 2 weight %). In some embodiments, the Al in FCC_A1 at 1500K can be above 4 weight % (or about 4 weight %). In some embodiments, the Al in FCC_A1 at 1500K can be above 6 weight % (or about 6 weight %).

A fifth thermodynamic criteria relates to the alloy's melting temperature and is defined as the liquidus temperature of the alloy [203]. In this alloy system, the M₇C₃ or M23C6 carbide is the first phase to form. Therefor the liquidus temperature is generally the formation temperature of the M₇C₃ or M23C6 carbide. This criteria is advantageous for the powder atomization process. If the liquidus temperature is too high, then it may not be possible to atomize the alloy. It becomes critical then to control the liquidus temperature of the alloy and ensure it remains below a certain point.

In some embodiments, the liquidus temperature of the alloy can be below 1975K (or about 1975K). In some embodiments, the liquidus temperature of the alloy can be below 1950K (or about 1950K). In some embodiments, the liquidus temperature of the alloy can be below 1900K (or about 1900K).

In some embodiments, a gamma phase matrix of the alloy can have an elevated Cr content as measured under equilibrium thermodynamic conditions at a temperature of 1300K. In such embodiments, it can be advantageous for the Cr content of the gamma matrix to exceed 15 (or about 15) wt. %. In some embodiments, the Cr content of the gamma matrix can exceed 17 (or about 17) wt. %. In some embodiments, the Cr content of the gamma matrix can exceed 20 (or about 20) wt. %. For example, the Cr content of the X3 alloy is 15.8 wt. % and the Cr content of the X9, X10, and X11 alloys exceed 20 wt. %.

In certain embodiments it is preferable to have further elevated Cr content in the matrix. In some embodiments, it is advantageous to have the Cr content of the gamma matrix exceed 30 (or about 30) wt. %. Such elevated gamma matrix Cr contents can be achieved while maintaining Cr₇C₃ as the carbide phase. In some embodiments, it can be advantageous to form Cr₂₃C₆ as the carbide phase to yet further increase gamma matrix Cr content. In such embodiments, it can be advantageous to have the Cr content of the gamma matrix exceed 35 (or about 35) wt. % In some embodiments, it can be advantageous to have the Cr content of the gamma matrix exceed 40 (or about 40) wt. %.

FIG. 7 shows the P105-X16 thermodynamic solidification profile of the P105-X16 alloy. As shown Cr₇C₃ forms at high temperatures [701], but ultimately Cr₂₃C₆ [702] forms. Thus the alloy will be predicted to form a gamma nickel [703] matrix with a mixture of Cr₇C₃ and Cr₂₃C₆ carbides. The total carbide content in P105-X16 is 60 mol. %.

In some embodiments, the feedstock can be characterized by having, under thermodynamic conditions at a temperature of 1300K, a matrix containing both a gamma phase and a beta phase both possessing an FCC structure, gamma being disordered and beta being ordered per conventional terminology, thus leading to a dual phase alloy. The beta content can range from 0 volume % up to a about a 1:1 gamma/ beta ratio. In heavy oxidation prone environments gamma/beta ratio can be 2.3 (or about 2.3) or lower. In some embodiments, the ratio can be between 0.7 and 1.5 (or between about 0.7 and about 1.5). The gamma/ beta ratio defines the matrix volume fraction, the entire alloy microstructure still containing 40-60 mol. % Cr₇C₃ carbides in that matrix. For example the X8 alloy has a M₇C₃ content of 55 mol. %, the γ/β matrix comprising the remaining 24 mol. %. The γ and β are phase fractions are essentially equal, 22.0 mol. % and 22.3 mol. % respectively equaling a γ/β ratio of 1.01.

FIG. 5 depicts the thermodynamic solidification profile of the P105-X8 alloy which is an exemplary embodiment of the dual phase matrix structure comprising gamma Nickel (depicted as FCC_A1 [502]) and beta (depicted as B2_BCC [503]). As shown gamma and beta have a 1:1 ratio at 22-25 mol. % at 1300K, and the remainder of the microstructure is the Cr₇C₃ phase [501]. The Cr₇C₃ carbide content is 55-58 mol. % in P105-X8. FIG. 6 illustrates a scanning electron micrograph of the alloy, with the Cr₇C₃ phase [601], gamma phase [602], and beta phase [603].

Table III lists all the experimental alloys which meet the three thermodynamic criterial and their calculated thermodynamic results.

TABLE III List of Calculated Thermodynamic Criteria for Experimental Alloys Phase FCC_A1 Fraction Cr₇C₃ Single- Al in of Cr₇C₃ @ Phase Phase FCC_Al @ Liquidus Alloy 1300 K Range Range 1500 K Temp. P105-X1 66.6 mol. % 1250 K  0 K 10.4 wt. % 2000 K P105-X2 63.5 mol. %  450 K 100 K 10.4 wt. % 1950 K P105-X3 57.9 mol. % 1000 K 725 K  4.0 wt. % 1900 K

In general, it can be advantageous to form an alloy that contains only Cr₇C₃ carbide and FCC Ni—Cr—Al with the lowest liquidus temperature possible and the highest amount of Al content in the FCC Ni—Cr—Al matrix phase. The phase fraction of Cr₇C₃ carbide can be varied to control the overall abrasion resistance of the alloy. However, adjusting the phase fraction of Cr₇C₃ carbide changes the chemistry of the FCC matrix phase. In general, an increased Cr₇C₃ content will reduce the available aluminum content in the γ phase when the other Table III criteria are set as described. Alloys which simultaneously maximize Cr₇C₃ and Al fraction in the γ phase can be described by Equation A.

0.7≤y+6.36x  Equation A

-   -   x is equal to the weight % Al in FCC_A1 at 1500K     -   y is equal to the phase mole fraction of Cr₇C₃ at 1500K

Once this equation is met, a relationship can also be show in the form of an equation between the Al and Ni content of the alloy (Equation B) and the C and Cr content of the alloy (Equation C).

(−6)≥y−0.20x≥(−9)  Equation B

-   -   x is equal to weight % Ni in the alloy     -   y is equal to weight % Al in the alloy

(−0.4)≥y−0.1x≥(−1.5)  Equation C

-   -   x is equal to weight % Cr in the alloy     -   y is equal to weight % C in the alloy

In some embodiments, alloys can meet Equations A, B, and/or C. In some embodiments, alloys can meet one of A, B, and C. In some embodiments, alloys can meet all three of A, B, and C. In some embodiments, alloys can meet A and B. In some embodiments, alloys can meet A and C. In some embodiments, alloys can meet B and C.

Table IV lists the compositions of potential alloys which meet all the thermodynamic criteria and Table V lists the thermodynamic criteria for each alloy.

TABLE IV List of Alloys Which Meet all Thermodynamic Criteria Al C Cr Ni No wt. % wt. % wt. % wt. % 1 1.0 5.0 59.0 35.0 2 0.5 5.5 59.0 35.0 3 0.5 5.0 59.0 35.5 4 1.0 5.0 58.0 36.0 5 0.5 5.5 58.0 36.0 6 0.5 5.0 58.0 36.5 7 1.0 5.0 57.0 37.0 8 0.5 5.0 57.0 37.5 9 1.0 5.0 56.0 38.0 10 0.5 5.0 56.0 38.5 11 1.0 5.0 55.0 39.0 12 1.0 4.5 55.0 39.5 13 1.5 5.0 54.0 39.5 14 0.5 5.0 55.0 39.5 15 1.0 5.0 54.0 40.0 16 1.5 4.5 54.0 40.0 17 1.0 4.5 54.0 40.5 18 1.5 5.0 53.0 40.5 19 2.0 4.5 53.0 40.5 20 0.5 5.0 54.0 40.5 21 1.5 4.5 53.0 41.0 22 1.0 4.5 53.0 41.5 23 2.0 4.5 52.0 41.5 24 1.5 4.5 52.0 42.0 25 1.0 4.5 52.0 42.5 26 2.0 4.5 51.0 42.5 27 1.5 4.5 51.0 43.0 28 1.0 4.5 51.0 43.5 29 2.0 4.5 50.0 43.5 30 1.5 4.5 50.0 44.0 31 2.5 4.5 49.0 44.0 32 1.0 4.5 50.0 44.5 33 2.0 4.5 49.0 44.5 34 1.5 4.5 49.0 45.0 35 2.0 4.0 49.0 45.0 36 2.5 4.5 48.0 45.0 37 1.0 4.5 49.0 45.5 38 2.0 4.5 48.0 45.5 39 2.5 4.0 48.0 45.5 40 2.0 4.0 48.0 46.0 41 2.5 4.0 47.0 46.5 42 2.0 4.0 47.0 47.0 43 2.5 4.0 46.0 47.5 44 2.0 4.0 46.0 48.0 45 3.0 4.0 45.0 48.0 46 2.5 4.0 45.0 48.5 47 2.0 4.0 45.0 49.0 48 2.5 3.5 45.0 49.0 49 3.0 4.0 44.0 49.0 50 2.5 4.0 44.0 49.5 51 3.0 3.5 44.0 49.5 52 2.0 4.0 44.0 50.0 53 2.5 3.5 44.0 50.0 54 3.0 4.0 43.0 50.0 55 3.5 3.5 43.0 50.0 56 2.5 4.0 43.0 50.5 57 3.0 3.5 43.0 50.5 58 2.5 3.5 43.0 51.0 59 3.5 3.5 42.0 51.0 60 3.0 3.5 42.0 51.5 61 2.5 3.5 42.0 52.0 62 3.5 3.5 41.0 52.0 63 3.0 3.5 41.0 52.5 64 2.5 3.5 41.0 53.0 65 3.5 3.5 40.0 53.0 66 3.0 3.5 40.0 53.5 67 4.0 3.5 39.0 53.5 68 2.5 3.5 40.0 54.0 69 3.5 3.5 39.0 54.0 70 3.0 3.5 39.0 54.5 71 3.5 3.0 39.0 54.5 72 4.0 3.5 38.0 54.5 73 2.5 3.5 39.0 55.0 74 3.5 3.5 38.0 55.0 75 4.0 3.0 38.0 55.0 76 3.5 3.0 38.0 55.5 77 4.0 3.0 37.0 56.0 78 3.5 3.0 37.0 56.5 79 4.5 3.0 36.0 56.5 80 4.0 3.0 36.0 57.0 81 3.5 3.0 36.0 57.5 82 4.5 3.0 35.0 57.5 83 4.0 3.0 35.0 58.0 84 3.5 3.0 35.0 58.5 85 4.5 3.0 34.0 58.5 86 4.0 3.0 34.0 59.0 87 4.5 2.5 34.0 59.0 88 5.0 3.0 33.0 59.0 89 3.5 3.0 34.0 59.5 90 4.5 3.0 33.0 59.5 91 5.0 2.5 33.0 59.5 92 4.0 3.0 33.0 60.0 93 4.5 2.5 33.0 60.0 94 5.5 2.5 32.0 60.0 95 5.0 2.5 32.0 60.5 96 6.0 2.5 31.0 60.5 97 4.5 2.5 32.0 61.0 98 5.5 2.5 31.0 61.0 99 5.0 2.5 31.0 61.5 100 6.0 2.5 30.0 61.5 101 4.5 2.5 31.0 62.0 102 5.5 2.5 30.0 62.0 103 5.0 2.5 30.0 62.5 104 6.0 2.5 29.0 62.5 105 4.5 2.5 30.0 63.0 106 5.5 2.5 29.0 63.0 107 6.5 2.5 28.0 63.0 108 5.0 2.5 29.0 63.5 109 6.0 2.5 28.0 63.5 110 4.5 2.5 29.0 64.0 111 5.5 2.5 28.0 64.0 112 6.0 2.0 28.0 64.0 113 5.5 2.0 28.0 64.5 114 6.5 2.0 27.0 64.5 115 6.0 2.0 27.0 65.0 116 5.5 2.0 27.0 65.5 117 6.5 2.0 26.0 65.5 118 6.0 2.0 26.0 66.0 119 5.5 2.0 26.0 66.5 120 6.5 2.0 25.0 66.5 121 6.0 2.0 25.0 67.0 122 7.0 2.0 24.0 67.0 123 5.5 2.0 25.0 67.5 124 6.5 2.0 24.0 67.5 125 6.0 2.0 24.0 68.0 126 5.5 2.0 24.0 68.5 127 6.5 1.5 23.0 69.0 128 7.0 1.5 22.0 69.5 129 6.5 1.5 22.0 70.0 130 7.0 1.5 21.0 70.5 131 6.5 1.5 21.0 71.0 132 7.0 1.5 20.0 71.5 133 6.5 1.5 20.0 72.0 134 7.5 1.5 19.0 72.0 135 7.0 1.5 19.0 72.5

TABLE V List of Thermodynamic Criteria for Each Alloy Cr₇C₃ @ Cr₇C₃ Phase FCC_A1 Single- Al in FCC_A1 Liquidus No 1300 K Range (K) Phase Range (K) @ 1500 K (K) Eq. A Eq. B Eq. C 1 63.5% 900 650 2.3% 1900 0.78 −6.0 −0.9 2 69.0% 1900 1650 1.3% 1900 0.77 −6.5 −0.4 3 63.7% 1000 750 1.1% 1900 0.71 −6.6 −0.9 4 63.5% 1000 750 2.3% 1900 0.78 −6.2 −0.8 5 69.0% 900 650 1.3% 1900 0.77 −6.7 −0.3 6 63.8% 1150 900 1.1% 1900 0.71 −6.8 −0.8 7 63.6% 1150 900 2.3% 1900 0.78 −6.4 −0.7 8 63.8% 1300 1050 1.1% 1900 0.71 −7.0 −0.7 9 63.6% 1300 1050 2.3% 1900 0.78 −6.6 −0.6 10 63.8% 1900 1650 1.1% 1900 0.71 −7.2 −0.6 11 63.7% 1900 1650 2.3% 1900 0.78 −6.8 −0.5 12 58.2% 900 650 2.0% 1900 0.71 −6.9 −1.0 13 63.5% 1900 1650 3.4% 1900 0.85 −6.4 −0.4 14 63.8% 1900 1650 1.1% 1900 0.71 −7.4 −0.5 15 63.7% 1900 1650 2.3% 1900 0.78 −7.0 −0.4 16 58.1% 900 650 3.0% 1900 0.77 −6.5 −0.9 17 58.3% 1050 800 2.0% 1900 0.71 −7.1 −0.9 18 63.5% 1900 1650 3.4% 1900 0.85 −6.6 −0.3 19 57.9% 950 700 4.0% 1900 0.83 −6.1 −0.8 20 63.8% 1900 1650 1.1% 1900 0.71 −7.6 −0.4 21 58.1% 1050 800 3.0% 1900 0.77 −6.7 −0.8 22 58.3% 1150 900 2.0% 1900 0.71 −7.3 −0.8 23 57.9% 1050 800 4.0% 1900 0.83 −6.3 −0.7 24 58.1% 1150 900 3.0% 1900 0.77 −6.9 −0.7 25 58.4% 1300 1050 2.0% 1900 0.71 −7.5 −0.7 26 58.0% 1200 950 4.0% 1900 0.83 −6.5 −0.6 27 58.2% 1300 1050 3.0% 1900 0.77 −7.1 −0.6 28 58.4% 1900 1650 2.0% 1900 0.71 −7.7 −0.6 29 58.0% 1300 1050 4.0% 1900 0.83 −6.7 −0.5 30 58.2% 1900 1650 3.0% 1900 0.77 −7.3 −0.5 31 57.8% 1350 1100 5.0% 1900 0.90 −6.3 −0.4 32 58.4% 1900 1650 2.0% 1900 0.71 −7.9 −0.5 33 58.0% 1900 1650 4.0% 1900 0.84 −6.9 −0.4 34 58.3% 1900 1650 3.0% 1900 0.77 −7.5 −0.4 35 52.4% 950 700 3.6% 1900 0.75 −7.0 −0.9 36 57.9% 1900 1650 5.0% 1900 0.90 −6.5 −0.3 37 58.4% 1900 1650 2.0% 1900 0.71 −8.1 −0.4 38 58.1% 1900 1650 4.0% 1900 0.84 −7.1 −0.3 39 52.2% 950 700 4.5% 1900 0.81 −6.6 −0.8 40 52.5% 1050 800 3.6% 1900 0.75 −7.2 −0.8 41 52.3% 1100 850 4.5% 1900 0.81 −6.8 −0.7 42 52.5% 1150 900 3.6% 1900 0.75 −7.4 −0.7 43 52.3% 1200 950 4.5% 1900 0.81 −7.0 −0.6 44 52.6% 1300 1050 3.6% 1900 0.75 −7.6 −0.6 45 52.2% 1200 950 5.4% 1900 0.87 −6.6 −0.5 46 52.4% 1300 1050 4.5% 1900 0.81 −7.2 −0.5 47 52.6% 1900 1650 3.6% 1900 0.75 −7.8 −0.5 48 46.6% 900 650 4.1% 1900 0.73 −7.3 −1.0 49 52.2% 1350 1100 5.4% 1900 0.87 −6.8 −0.4 50 52.4% 1900 1650 4.5% 1900 0.81 −7.4 −0.4 51 46.4% 900 650 4.9% 1900 0.78 −6.9 −0.9 52 52.6% 1900 1650 3.6% 1900 0.75 −8.0 −0.4 53 46.6% 1000 750 4.1% 1900 0.73 −7.5 −0.9 54 52.2% 1900 1650 5.4% 1900 0.87 −7.0 −0.3 55 46.2% 900 650 5.7% 1900 0.83 −6.5 −0.8 56 52.5% 1900 1650 4.5% 1900 0.81 −7.6 −0.3 57 46.5% 1000 750 4.9% 1900 0.78 −7.1 −0.8 58 46.7% 1100 850 4.1% 1900 0.73 −7.7 −0.8 59 46.3% 1000 750 5.7% 1900 0.83 −6.7 −0.7 60 46.5% 1100 850 4.9% 1900 0.78 −7.3 −0.7 61 46.7% 1200 950 4.1% 1900 0.73 −7.9 −0.7 62 46.3% 1100 850 5.7% 1900 0.83 −6.9 −0.6 63 46.5% 1200 950 4.9% 1900 0.78 −7.5 −0.6 64 46.7% 1300 1050 4.1% 1900 0.73 −8.1 −0.6 65 46.4% 1200 950 5.7% 1900 0.83 −7.1 −0.5 66 46.6% 1300 1050 4.9% 1900 0.78 −7.7 −0.5 67 46.2% 1250 1000 6.6% 1900 0.88 −6.7 −0.4 68 46.8% 1900 1650 4.1% 1900 0.73 −8.3 −0.5 69 46.4% 1350 1100 5.8% 1900 0.83 −7.3 −0.4 70 46.6% 1900 1650 4.9% 1900 0.78 −7.9 −0.4 71 40.4% 950 700 5.3% 1900 0.74 −7.4 −0.9 72 46.3% 1350 1100 6.6% 1900 0.88 −6.9 −0.3 73 46.8% 1900 1650 4.1% 1900 0.73 −8.5 −0.4 74 46.5% 1900 1650 5.8% 1900 0.83 −7.5 −0.3 75 40.3% 950 700 6.0% 1900 0.78 −7.0 −0.8 76 40.5% 1000 750 5.3% 1900 0.74 −7.6 −0.8 77 40.3% 1050 800 6.0% 1900 0.79 −7.2 −0.7 78 40.5% 1100 850 5.3% 1900 0.74 −7.8 −0.7 79 40.2% 1050 800 6.8% 1900 0.83 −6.8 −0.6 80 40.4% 1150 900 6.0% 1900 0.79 −7.4 −0.6 81 40.6% 1200 950 5.3% 1900 0.74 −8.0 −0.6 82 40.2% 1150 900 6.8% 1900 0.83 −7.0 −0.5 83 40.4% 1250 1000 6.0% 1900 0.79 −7.6 −0.5 84 40.6% 1300 1050 5.3% 1900 0.74 −8.2 −0.5 85 40.3% 1250 1000 6.8% 1900 0.83 −7.2 −0.4 86 40.4% 1350 1100 6.0% 1900 0.79 −7.8 −0.4 87 34.1% 900 650 6.2% 1900 0.74 −7.3 −0.9 88 40.1% 1300 1050 7.5% 1900 0.88 −6.8 −0.3 89 40.6% 1900 1650 5.3% 1900 0.74 −8.4 −0.4 90 40.3% 1350 1100 6.8% 1900 0.83 −7.4 −0.3 91 34.0% 900 650 6.9% 1900 0.78 −6.9 −0.8 92 40.5% 1900 1650 6.0% 1900 0.79 −8.0 −0.3 93 34.1% 1000 750 6.2% 1900 0.74 −7.5 −0.8 94 33.8% 950 700 7.6% 1900 0.82 −6.5 −0.7 95 34.0% 1000 750 6.9% 1900 0.78 −7.1 −0.7 96 33.7% 1000 750 8.3% 1900 0.87 −6.1 −0.6 97 34.2% 1050 800 6.2% 1900 0.74 −7.7 −0.7 98 33.9% 1050 800 7.6% 1900 0.82 −6.7 −0.6 99 34.0% 1100 850 6.9% 1900 0.78 −7.3 −0.6 100 33.8% 1100 850 8.3% 1900 0.87 −6.3 −0.5 101 34.2% 1150 900 6.2% 1900 0.74 −7.9 −0.6 102 33.9% 1100 850 7.6% 1900 0.82 −6.9 −0.5 103 34.1% 1150 900 6.9% 1900 0.78 −7.5 −0.5 104 33.8% 1200 950 8.3% 1900 0.87 −6.5 −0.4 105 34.2% 1250 1000 6.2% 1900 0.74 −8.1 −0.5 106 33.9% 1200 950 7.6% 1900 0.82 −7.1 −0.4 107 33.7% 1250 1000 9.0% 1900 0.91 −6.1 −0.3 108 34.1% 1250 1000 6.9% 1900 0.78 −7.7 −0.4 109 33.8% 1300 1050 8.3% 1900 0.87 −6.7 −0.3 110 34.3% 1350 1100 6.2% 1900 0.74 −8.3 −0.4 111 34.0% 1300 1050 7.6% 1900 0.83 −7.3 −0.3 112 27.5% 900 650 7.7% 1900 0.77 −6.8 −0.8 113 27.6% 950 700 7.1% 1900 0.73 −7.4 −0.8 114 27.4% 900 650 8.4% 1900 0.81 −6.4 −0.7 115 27.5% 950 700 7.7% 1900 0.77 −7.0 −0.7 116 27.7% 1000 750 7.1% 1900 0.73 −7.6 −0.7 117 27.4% 1000 750 8.4% 1900 0.81 −6.6 −0.6 118 27.6% 1050 800 7.7% 1900 0.77 −7.2 −0.6 119 27.7% 1100 850 7.1% 1900 0.73 −7.8 −0.6 120 27.5% 1100 850 8.4% 1900 0.81 −6.8 −0.5 121 27.6% 1150 900 7.7% 1900 0.77 −7.4 −0.5 122 27.4% 1200 650 9.0% 1900 0.85 −6.4 −0.4 123 27.7% 1150 950 7.1% 1850 0.73 −8.0 −0.5 124 27.5% 1200 950 8.4% 1900 0.81 −7.0 −0.4 125 27.6% 1200 950 7.7% 1900 0.77 −7.6 −0.4 126 27.7% 1250 1050 7.1% 1850 0.73 −8.2 −0.4 127 21.0% 850 650 7.8% 1850 0.71 −7.3 −0.8 128 20.9% 900 650 8.4% 1850 0.74 −6.9 −0.7 129 21.0% 950 750 7.8% 1850 0.71 −7.5 −0.7 130 20.9% 1000 800 8.4% 1850 0.74 −7.1 −0.6 131 21.0% 1000 800 7.8% 1850 0.71 −7.7 −0.6 132 20.9% 1100 900 8.4% 1850 0.74 −7.3 −0.5 133 21.0% 1100 900 7.8% 1850 0.71 −7.9 −0.5 134 20.9% 1150 650 9.0% 1850 0.78 −6.9 −0.4 135 21.0% 1150 950 8.4% 1850 0.74 −7.5 −0.4

Microstructure Criteria

In some embodiments, the alloys are fully described by microstructural criteria. The alloys can meet some, or all, of the described microstructural criteria.

The first microstructural criteria is related to the total measured area fraction of Cr₇C₃ particles [301], as shown in FIG. 3. Area % can be used when measuring phase fractions in a micrograph. This is because a micrograph is a two-dimensional image of the alloy's microstructure. So, when the phase fraction in a micrograph is measured, it is really measuring the area fraction of a phase as opposed to the volume fraction of a phase.

In some embodiments, the alloy can possess at least 40 area % (or about 40 area %) of Cr₇C₃ particles. In some embodiments, the alloy can possess at least 50 area % (or about 50 area %) of Cr₇C₃ particles. In some embodiments, the alloy can possess at least 60 area % (or about 60 area %) of Cr₇C₃ particles.

In some embodiments, the alloy can possess at least 30 area % (or about 30 area %) of Cr₂₃C₆ particles. In some embodiments, the alloy can possess at least 35 area % (or about 35 area %) of Cr₂₃C₆₃ particles. In some embodiments, the alloy can possess at least 40 area % (or about 40 area %) of Cr₂₃C₆ particles.

The second microstructural criterion relates to the Al content in the matrix phase of the alloy. Energy dispersive spectroscopy (EDS) is used to measure the weight % Al content in the alloy's matrix phase [302]. In some embodiments, the total Al content in the matrix can be 4 weight % (or about 4 weight %) or higher. In some embodiments, the total Al content in the matrix can be 6 weight % (or about 6 weight %) or higher. In some embodiments, the total Al content in the matrix must be 9 weight % (or about 9 weight %) or higher.

Table lists all the experimentally measured microstructural criteria results for the alloys producing in the study.

TABLE V List of Experimentally Measured Microstructural Criteria for Experimental Alloys Area Fraction of EDS Al in Matrix Alloy Cr₇C₃ Measurement P105-X1 68.5% 8.8 wt. % P105-X2 62.7% 10.6 wt. %  P105-X3 51.8% 4.1 wt. %

The table below shows the experimentally measured microstructural criteria for the higher Cr in the gamma matrix alloys.

TABLE VI Experimental Results Modeled Cr Measured Cr Modeled M₇C₃ Measured M₇C₃ Modeled M₂₃C₆ Measured M₂₃C₆ No. in Matrix in Matrix Fraction Fraction Fraction Fraction P105-X13 23.3 33.9 44.0 40.8 P105-X16 34.0 43.8 40.0 45.0

Performance Criteria

In some embodiments, the alloy can be described by meeting certain desirable performance characteristics. It can be advantageous for embodiments of the disclose alloy to simultaneously have 1) a high resistance to abrasive wear, 2) a high resistance to cavitation 3) a certain hardness as an HVOF coating 4) a high impact resistance and 5) good corrosion resistance.

Abrasion resistance can be quantified by the ASTM G65B test. In some embodiments, the hardfacing layer can have an ASTM G65B volume loss of less than 35 (or about 35) mm³. some embodiments, the hardfacing layer can have an ASTM G65B volume loss of less than 25 (or about 25) mm³. In some embodiments, the hardfacing layer can have an ASTM G65B volume loss of less than 15 (or about 15) mm³.

Cavitation resistance can be quantified by the ASTM G32 test, and relates to the resistance of a material to tiny gas bubble explosions which may occur in turbulent liquid flow, such as for turbines on ships or hydroelectric dams. In some embodiments, the hardfacing layer can have an ASTM G32 volume loss of less than 5 (or about 5) mm³ after 1200 minutes. In some embodiments, the hardfacing layer can have an ASTM G32 volume loss of less than 4 (or about 4) mm³ after 1200 minutes. In some embodiments, the hardfacing layer can have an ASTM G32 volume loss of less than 3 (or about 3) mm³ after 1200 minutes. In some embodiments, the hardfacing layer can have an ASTM G32 volume loss of less than 2.5 (or about 2.5) mm³ after 1200 minutes.

The table below details cavitation of the alloys disclosed here (P104-X3 and P105-X8) in addition to other relevant alloys. As shown the alloys developed here exhibit improved cavitation resistance than standard atomized Ni—Cr—C as well as agglomerated and sintered Ni—Cr—CrC powder. In this table the atomized Ni—Cr—C is within the general range: Ni: balance, Cr: 40-60, C: 5-8 with Mn and Si as atomizing aids, and the agglomerated and sintered material is Cr: balance, C: 8-11, Ni: 15-30.

TABLE VII Cavitation Resistance Analysis Cavitation Resistance Alloy (Volume Loss after 1200 minutes) P105-X3 1.88 mm³ P105-X8 2.12 mm³ Atomized Ni—Cr—C 2.74 mm³ Agglomerated and Sintered Cr—C 4.02 mm³

Hardness of the alloy as applied via the HVOF thermal spray process can be quantified in Vickers hardness. In some embodiments, the hardfacing layer can have a Vickers hardness of greater than 500 (or about 500) HV_(0.3). In some embodiments, the hardfacing layer can have Vickers hardness of greater than 600 (or about 600) HV_(0.3). In some embodiments, the hardfacing layer can have Vickers hardness of greater than 700 (or about 700) HV_(0.3).

The impact resistance is quantified by a static impact test, such as ASTM D2794. In some embodiments, the hardfacing layer lasts over 30 impacts before failing. In some embodiments, the hardfacing layer lasts over 40 impacts before failing. In some embodiments, the hardfacing layer lasts over 50 impacts before failing. The P105-X3 and P105-X8 alloys can be subject to 50 impacts without fail, whereas the agglomerated and sintered Cr—C coating fails after 1-3 impacts.

Corrosion resistance can be quantified by the ASTM B117 salt spray test. In some embodiments, the hardfacing layer can last over 500 (or about 500) hours before failing. In some embodiments, the hardfacing layer can last over 750 (or about 750) hours before failing. In some embodiments, the hardfacing layer can last over 1000 (or about 1000) hours before failing.

Deposit efficiency and is the ratio of material that adheres to the subject with the total amount of material which is sprayed through the gun. Higher deposition efficiencies are desirable as they equate to a more efficient process in terms of both time and material consumption. P105-X3 exhibited a deposit efficiency of 42% in comparison to the deposit efficiency in the agglomerated and sintered Cr—C of 29.7%. In some embodiments, the deposit efficiency is 30 (or about 30) % or greater. In some embodiments, the deposit efficiency is 40 (or about 40)% or greater.

The disclosed alloys can also have high resistance to metal dusting whereby they exhibit minimal material loss in a high temperature carbon rich environment. The disclosed alloys are additionally optimal in metal dusting environments which is simultaneously erosive.

The disclosed alloys can function in high temperature, such as up to 850° C., unlubricated sliding wear applications.

The disclosed alloys can function in blade tipping applications whereby they can act as a cutting surface into a mating abradables coating. In such an application the alloy can retain high hot hardness in addition to oxidation resistance.

Example 1

This example demonstrates how the single-phase FCC_A1 temperature range can be advantageous for designing an alloy with a single-phase matrix. As shown in FIG. 4, note that alloy X1 has a single-phase FCC_A1 range of 0K and alloy X3 has a single-phase FCC_A1 range of 725K. After both alloys were manufactured, a significant difference between the two can be observed. The matrix of alloy X1, with the single-phase range of 0K, is multi-phase [401]. In contrast, the matrix of alloy X3, with the single-phase range of 725K, is single phase [402]. Thus, it can be appreciated that the single-phase FCC_A1 range provides a useful measure of the matrix phase and stability.

Example 2

The second example demonstrates an alloy that was successfully gas atomized into a powder and HVOF sprayed to form a coating. The alloy P105-X3 was gas atomized using argon gas and sieved to a particle size range of −53+20 μm. The resultant atomized powder chemistry was measured and listed in Table VI. The powder was then sprayed through a WokaJet 400 HVOF gun to form a coating. Table VII lists the HVOF spray parameters used to form the coating. Finally, the coating was analyzed, and the results are listed in Table VIII. The alloy P105-X3 meets all the thermodynamic, microstructural and performance criteria of this disclosure.

TABLE VI Chemical Analysis Results for Gas Atomized P105-X3 Powder (wt. %) Al C Cr Ni Nitrogen Oxygen T.A.O 2.14 4.28 52.51 Bal. 0.01 0.02 <0.50

TABLE VII HVOF Spray Parameters for WokaJet 400 Oxygen Flow 950 l/min Nitrogen Flow 344 l/min Fuel Flow 24.3 l/hr Fuel Type Kerosene Powder Feed Rate 29.3 g/min Spray Distance 300 mm Surface Speed 80 m/min Coating Thickness 320 μm Application Rate 16 μ/pass Deposit Efficiency 42-43%

TABLE VIII P105-X3 Coating Analysis Results Test Result Coating Microhardness 749 HV_(0.3) ASTM G65B Volume Loss 12.44 mm³ ASTM G32 Volume Loss 1.878 mm³ after 1200 min Static Impact Test 50 impacts no damage ASTM B117 1000 hrs Suga Wear Test Volume Loss 19.64 mm³

Applications

The alloys described in this patent can be used in a variety of applications and industries. Some non-limiting examples of applications of use include:

Surface Mining applications include the following components and coatings for the following components: Wear resistant sleeves and/or wear resistant hardfacing for slurry pipelines, mud pump components including pump housing or impeller or hardfacing for mud pump components, ore feed chute components including chute blocks or hardfacing of chute blocks, separation screens including but not limited to rotary breaker screens, banana screens, and shaker screens, liners for autogenous grinding mills and semi-autogenous grinding mills, ground engaging tools and teeth and hardfacing for ground engaging tools and teeth, shrouds and adapters, wear plate and rock boxes including for buckets and dumptruck liners, heel blocks and hardfacing for heel blocks on mining shovels, grader blades and hardfacing for grader blades, stacker reclaimers, sizer crushers, jaw crushers, ripper teeth, cutting edges, general wear packages for mining components and other comminution components.

Downstream oil and gas applications include the following components and coatings for the following components: Downhole casing and downhole casing, drill pipe and coatings for drill pipe including hardbanding, mud management components, mud motors, fracking pump sleeves, fracking impellers, fracking blender pumps, stop collars, drill bits and drill bit components, directional drilling equipment and coatings for directional drilling equipment including stabilizers and centralizers, blow out preventers and coatings for blow out preventers and blow out preventer components including the shear rams, oil country tubular goods and coatings for oil country tubular goods, sucker rods and couplings, lift plungers, neyfor rotors, artificial lift casing, and ESP pump housing and impellers, flowlines and subsea flowlines.

Upstream oil and gas applications include the following components and coatings for the following components: Process vessels and coating for process vessels including steam generation equipment, amine vessels, distillation towers, cyclones, catalytic crackers, general refinery piping, corrosion under insulation protection, sulfur recovery units, convection hoods, sour stripper lines, scrubbers, hydrocarbon drums, and other refinery equipment and vessels.

Pulp and paper applications include the following components and coatings for the following components: Rolls used in paper machines including yankee dryers, through air dryers, and other dryers, calendar rolls, machine rolls, press rolls, winding rolls, digesters, pulp mixers, pulpers, pumps, boilers, shredders, tissue machines, roll and bale handling machines, fiber guidance systems such as deflector blades, doctor blades, evaporators, pulp mills, head boxes, wire parts, press parts, M.G. cylinders, pope reels, winders, vacuum pumps, deflakers, and other pulp and paper equipment.

Power generation applications include the following components and coatings for the following components: boiler tubes, precipitators, fireboxes, turbines, generators, cooling towers, condensers, chutes and troughs, augers, bag houses, ducts, ID fans, coal piping, and other power generation components.

Agriculture applications include the following components and coatings for the following components: chutes, base cutter blades, sugar cane harvesting knives, hammers, troughs, primary fan blades, secondary fan blades, augers, components common to mining applications, and other agricultural applications.

Construction applications include the following components and coatings for the following components: cement chutes, cement piping, bag houses, mixing equipment and other construction applications.

Machine element applications include the following components and coatings for the following components: Shaft journals, hydraulic cylinders, paper rolls, gear boxes, drive rollers, impellers, rebuilding of engine decks, propeller shafts and other shafts, general reclamation and dimensional restoration applications and other machine element applications.

Steel applications include the following components and coatings for the following components: cold rolling mills, hot rolling mills, wire rod mills, galvanizing lines, continue pickling lines, continuous casting rolls and other steel mill rolls, and other steel applications.

The alloys described herein can be produced and or deposited in a variety of techniques effectively. Some non-limiting examples of processes include:

Thermal spray processes including those using a wire feedstock such as twin wire arc, spray, high velocity arc spray, combustion spray and those using a powder feedstock such as high velocity oxygen fuel, high velocity air spray, plasma spray, detonation gun spray, and cold spray. Wire feedstock can be in the form of a metal core wire, solid wire, or flux core wire. Powder feedstock can be either a single homogenous alloy or a combination of multiple alloy powder which result in the desired chemistry when melted together.

Welding processes including those using a wire feedstock including but not limited to metal inert gas (MIG) welding, tungsten inert gas (TIG) welding, arc welding, submerged arc welding, open arc welding, bulk welding, laser cladding, and those using a powder feedstock including but not limited to laser cladding, ultra-high speed lasers cladding (EHLA), and plasma transferred arc welding. Wire feedstock can be in the form of a metal core wire, solid wire, or flux core wire. Powder feedstock can be either a single homogenous alloy or a combination of multiple alloy powder which result in the desired chemistry when melted together.

Casting processes including processes typical to producing cast iron including but not limited to sand casting, permanent mold casting, chill casting, investment casting, lost foam casting, die casting, centrifugal casting, glass casting, slip casting and process typical to producing wrought steel products including continuous casting processes.

Post processing techniques including but not limited to rolling, forging, surface treatments such as carburizing, nitriding, carbonitriding, heat treatments including but not limited to austenitizing, normalizing, annealing, stress relieving, tempering, aging, quenching, cryogenic treatments, flame hardening, induction hardening, differential hardening, case hardening, decarburization, machining, grinding, cold working, work hardening, and welding.

From the foregoing description, it will be appreciated that inventive products and approaches for powder feedstocks are disclosed. While several components, techniques and aspects have been described with a certain degree of particularity, it is manifest that many changes can be made in the specific designs, constructions and methodology herein above described without departing from the spirit and scope of this disclosure.

Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as any subcombination or variation of any subcombination.

Moreover, while methods may be depicted in the drawings or described in the specification in a particular order, such methods need not be performed in the particular order shown or in sequential order, and that all methods need not be performed, to achieve desirable results. Other methods that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional methods can be performed before, after, simultaneously, or between any of the described methods. Further, the methods may be rearranged or reordered in other implementations. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. Additionally, other implementations are within the scope of this disclosure.

Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include or do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments.

Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than or equal to 10% of, within less than or equal to 5% of, within less than or equal to 1% of, within less than or equal to 0.1% of, and within less than or equal to 0.01% of the stated amount. If the stated amount is 0 (e.g., none, having no), the above recited ranges can be specific ranges, and not within a particular % of the value. For example, within less than or equal to 10 wt./vol. % of, within less than or equal to 5 wt./vol. % of, within less than or equal to 1 wt./vol. % of, within less than or equal to 0.1 wt./vol. % of, and within less than or equal to 0.01 wt./vol. % of the stated amount.

Some embodiments have been described in connection with the accompanying drawings. The figures are drawn to scale, but such scale should not be limiting, since dimensions and proportions other than what are shown are contemplated and are within the scope of the disclosed inventions. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, it will be recognized that any methods described herein may be practiced using any device suitable for performing the recited steps.

While a number of embodiments and variations thereof have been described in detail, other modifications and methods of using the same will be apparent to those of skill in the art. Accordingly, it should be understood that various applications, modifications, materials, and substitutions can be made of equivalents without departing from the unique and inventive disclosure herein or the scope of the claims. 

1. A thermal spray feedstock comprising: Ni; Al: about 1.0 wt. %-about 3.0 wt. %; C: about 3.5 wt. %-about 5.5 wt. %; and Cr: about 47.5 wt. %-about 57.5 wt. %; wherein the feedstock is configured to form CrC carbides.
 2. (canceled)
 3. The thermal spray feedstock of claim 1, wherein the CrC carbides comprise Cr₇C₃ carbides.
 4. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, a total Cr₇C₃ fraction at 1300K of about 40 mole % or greater.
 5. (canceled)
 6. (canceled)
 7. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, a temperature range of at least about 400K when Cr₇C₃ carbides are the only carbides present.
 8. (canceled)
 9. (canceled)
 10. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, a temperature range of a single-phase FCC_A1 matrix of at least about 200K.
 11. (canceled)
 12. (canceled)
 13. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, a weight percentage of aluminum content in a single phase FCC_A1 matrix at 1500K of above about 2%.
 14. (canceled)
 15. (canceled)
 16. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, a liquidus temperature of below about 1975K.
 17. (canceled)
 18. (canceled)
 19. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation 0.7≥y+6.36x, x being equal to a weight % of Al in an FCC_A1 matrix at 1500K and y being equal to a phase mole fraction of Cr₇C₃ at 1500K.
 20. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation (−6)≥y−0.20x≥(−9), x being equal to a wt. % Ni and y being equal to a wt. % Al.
 21. The thermal spray feedstock of claim 1, wherein the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation (−0.4)≥y−0.1x≥(−1.5), x being equal to a wt. % Cr and y being equal to a wt. % C.
 22. The thermal spray feedstock of claim 1, wherein the thermal spray feedstock is boron free.
 23. (canceled)
 24. (canceled)
 25. (canceled)
 26. (canceled)
 27. (canceled)
 28. (canceled)
 29. The thermal spray feedstock of claim 1, wherein the thermal spray feedstock is a powder.
 30. A hardfacing coating formed from the thermal spray feedstock of claim 1, comprising CrC carbides.
 31. The hardfacing coating of claim 30, wherein the coating has at least about 40 area % of Cr₇C₃ particles.
 32. (canceled)
 33. (canceled)
 34. The hardfacing coating of claim 30, wherein the coating has a matrix comprising a total Al content of about 4 weight % or higher.
 35. (canceled)
 36. (canceled)
 37. The hardfacing coating of claim 30, wherein the coating has an ASTM G65B volume loss of less than about 35 mm³.
 38. (canceled)
 39. (canceled)
 40. The hardfacing coating of claim 30, wherein the coating has an ASTM G32 volume loss of less than about 5 mm³ after 1200 minutes.
 41. (canceled)
 42. (canceled)
 43. The hardfacing coating of claim 30, wherein the coating has a Vickers hardness of greater than about 500 HV_(0.3).
 44. (canceled)
 45. (canceled)
 46. The hardfacing coating of claim 30, wherein the coating can last over about 500 hours before failing under ASTM B117 salt spray testing.
 47. (canceled)
 48. (canceled)
 49. (canceled)
 50. A powder feedstock comprising: Ni; Al: about 5.6 wt. %-about 8.4 wt. %; C: about 3.6 wt. %-about 5.4 wt. %; and Cr: about 37.6 wt. %-about 56.4 wt. %; wherein the powder feedstock is configured to form CrC carbides.
 51. (canceled)
 52. (canceled) 